### Home > APCALC > Chapter 9 > Lesson 9.1.3 > Problem 9-45

9-45.

A variant of Ying’s method (manipulating an infinite sum so that the sum appears as a part of itself) can be used in other situations. For example, to evaluate the infinite “nested radical” below, let: Homework Help ✎

Explain why .

Which sum makes sense?